Fabrication and reliability investigation of copper pillar and tapered through silicon via (TSV) for direct bonding in 3D integration

Compare to the conventional structure, in this research, the structure of Cu pillar and tapered TSV for direct bonding has an excellent potential for low bonding temperature within a short bonding time. In addition, this scheme has the advantage of self-alignment ability. This paper focuses on the fabrication of taper-shape of through silicon via (TSV) and reports the quality and reliability investigation of bonding results.